Water saveall for grooved roll in paper machine press nip

ABSTRACT

In a paper machine press assembly formed by a pair of press rolls, one of which is circumferentially grooved and through which a press felt and a paper web pass, a saveall is mounted adjacent the ingoing side of the press nip between the press felt and the grooved roll. The saveall is formed with a planar bottom wall which extends away from the press nip in closely spaced relationship to the inner surface of the felt, a semicylindrical top wall which curves away from the felt back toward the grooved roll and a series of internal baffles which extend from the bottom and top walls inwardly of the saveall to both stiffen the unit and form a series of upwardly opening troughs which collect liquid expressed from the grooved roll at the ingoing side of the press nip.

United States Patent 1191 [11] 3,775,243 McCarrick Nov. 27, 1973 1 WATER SAVEALL FOR GROOVED ROLL 3,198,694 8/1965 Justus 162/272 x [75] Inventor: Terence E. McCarrick, Watertown,

[73] Assignee: The Black Clawson Company,

Hamilton, Ohio [22] Filed: June 1, 1970 [21] Appl. No.: 42,062

[52] US. Cl 162/272, l5/256.5l, 100/121, 162/199, 162/358 [51] Int. Cl. D2lf 3/02, D2lg 9/00 [58] Field of Search 162/48, 199, 272, 162/279, 358, 361, 363; 15/256511; 100/121, 90

[56] References Cited UNITED STATES PATENTS 2,858,747 11/1958 Wagner 162/361 3,355,350 11/1967 Reynolds 162/358 3,098,788 7/1963 l-Iornbostel 162/363 X 3,198,693 8/1965 Justus 162/272 IN PAPER MACHINE PRESS NIP Primary Examiner-S. Leon Bashore Assistant ExaminerRichard l-I. Tushin Attorney--Marechal, Biebel, French and Bugg 57 ABSTRACT In a paper machine press assembly formed by a pair of press rolls, one of which is circumferentially grooved and through which a press felt and a paper web pass, a saveall is mounted adjacent the ingoing side of the press nip between the press felt and the grooved roll. The saveall is formed with a planar bottom wall which extends away from the press nip in closely spaced relationship to the inner surface of the felt, a semicylindrical top wall which curves away from the felt back toward the grooved roll and a series of internal baffles which extend from the bottom and top walls inwardly of the saveall to both stiffen the unit and form a series of upwardly opening troughs which collect liquid expressed from the grooved roll at the ingoing side of the press nip.

6 Claims, 8 Drawing Figures BACKGROUND OF THE INVENTION In a press assembly of the type shown in U.S. Pat. No. 2,858,747, at least one of the rolls forming the press nip is provided with a circumferentially grooved outer surface which permits liquid expressed from a web passing through the press nip to enter the grooves; thereby greatly increasing the dewatering capacity of the press over that which would obtain with imperforate surfaced rollers. Of course, it is necessary to continuously remove from the grooves at least a substantial portion of the liquid which has been expressed into them and to this end a variety of devices have been developed. For example, in the above noted U.S. Pat. No. 2,858,747 suction devices are mounted on the ingoing side of the press nip to create a back flow of air through the nip to help remove liquid from the grooves into the suction devices. Additionally, the suction devices are provided with teeth which extend into the grooves to continuously doctor these portions of the roll. It will be apparent, however, that not only does the use of suction devices increase the power requirements of the system, but the use of fingers extending into the grooves of the rolls requires very precise manufacturing tolerances to prevent breakage or excessive wear of these interfitting components of the press assembly. Additionally, it will usually be desirable to 'form the grooves in the grooved roll as one or more spirally extending grooves rather than a series of parallel, radially extending grooves to prevent excessive localized wear where the grooved roll is in continuous contact with a member such as a papermaking felt, and it will be seen that if this expedient is practiced it is impossible to utilize a plurality of stationary fingers projecting into the grooves to doctor liquid therefrom.

SUMMARY OF THE INVENTION The present invention recognizes the fact that .the forces generated adjacent the ingoing side of the press nip cause liquid to be ejected from the grooves of the grooved roll without the necessity of suction devices, air jets and the like. .Thus, the present invention provides a saveall construction which is extremely compact and self-supporting and which is mounted adjacent the ingoing side of the press nip between a press felt wrapping the grooved roll and the surface of the groovedroll. The interior of the saveall is provided with a series of internal baffles which extend inwardly of the saveall away from the press nip and serve to both stiffen the saveall to provide a self-supporting unit and define a series of troughs which collect liquid expressed from the grooves of the grooved press roll and permit this liquid to be carried away from the press nip.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view showing a press assembly in accordance with the present invention;

FIG. 2 is a view of a portion of a grooved press roll of FIG. I; I

FIG. 3 is a front elevational view of the saveall of FIG. 1;

FIG. 4 is a view takerr on.-line 4--4 of FIG. 3;

FIG. 5 is a view takeii on line 5--5 of FIG. 3;

FIG. 6 is a view taken on line 6-6 of FIG. 3;

FIG. 7 is a view taken on line 7-7 of FIG. 3; and

FIG. 8 is a view of a component of the saveall.

DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in FIG. 1, a press assembly according to the present invention may comprise a first press roll 10, which conveniently may be formed as a suction roll. Roll 10 is wrapped by a felt 11 and forms a first press nip with a second press roll 13 which conveniently may be a smooth surfaced, granite roll. Roll 12 in turn forms a second press nip with an additional press roll 13 which, as seen in FIG. 2, is of grooved construction having a groove or series of grooves 16. Press roll 13 is wrapped by a porous belt 14, such as a papermaking felt, which also wraps a turning roll 15 downstream of the second press nip and the saveall 20 of the present invention is mounted at the ingoing side of the second press nip between the surface of the grooved roll 13 and the inner surface of the felt 14. A web W of paper or the like enters the press assembly from a right-hand side as seen in FIG. 1 and is trained about the various rolls of the press assembly in the direction indicated by the arrows.

Turning now to FIGS. 3 through 8 of the drawings, it will be seen that the saveall includes a substantially planar bottom wall 21 which has its lower edge positioned adjacent the ingoing side of the press nip formed by the rolls 12 and 13 and extends upstream away from the nip in closely spaced relationship to the inner surface of the porous belt 14. A semi-cylindrical top wall 22 has one longitudinal edge thereof attached to the upper longitudinal edge of the bottom wall 21 to, in effect, form a continuation of the bottom wall 21 which extends in a direction away from the belt 14 and terminates in a second longitudinal edge 23 positioned adjacent the surface of the grooved press roll 13.

A first planar baffle wall 24 has its lower edge attached by welding or the like to the lower edge of the bottom wall 21 and extends upwardly away from the lower edge of the bottom wall in diverging relationship thereto to form a first trough 25. A second planar internal baffle 26 has its lower edge attached to the bottom wall 21 intermediate the longitudinal edges thereof as by welding or the like to form a second trough 27. Mounted on the edge 23 of the semi-cylindrical upper wall 22 is a third planar internal baffle 28 which, with a portion of the top wall 22, forms a trough 29.

Extending from the upper edge 30 of baffle 24 to an intermediate portion of the baffle 26 are a series of plate-like struts 31, only one of which is shown, which are interconnected to the baffles 24 and 26 to provide additional rigidity to the unit. From the upper end 32 of the baffle 26 a second series of plate-like struts 33 are mounted and interconnected, by welding or the like, to an upper portion of the bottom wall 21. Similarly, a third series of struts 34 extend between portions of the top wall 22 and the internal baffle 28.

A plate member 40, FIG. 8, having a cut-out portion 41 of the same general configuration as the cross sectional configuration of the bottom wall 21 and the baffle 24, is attached to the saveall construction thus far described adjacent one end thereof, as best seen in FIG. 3. Plate member 40 together with an end cover plate 42 and front and back plates 43 and 44 form a header 45 for collecting liquid collected in the various troughs 25, 27 and 29. A conduit 46 is attached to the walls 40, 42, 43 and 44 for draining the header 45 while a cover plate 47 closes off the right-hand side, as seen in FIG. 3, of the saveall and a shroud 48 encloses the upper portion thereof.

With the press assembly described above, it will be seen that a partially dewatered web W of paper or the like is carried into the press assembly by the felt 11 and then through the first press nip formed by the rolls and 12. From the first press nip the web is trained about roll 12 in the direction indicated by the arrows and then through the nip formed by the roll 12 and the grooved roll 13 and thence, around a turning roller 15, from which it is directed into further press sections, dryers, or the like.

As the web passes through the nip formed by the rolls 12 and 13, water is expressed therefrom into the felt 14 and thence into the grooves 16 in the roll 13. As the roll 13 rotates back around towards the ingoing side of the press nip, sufficient pressure is generated adjacent this point to cause a substantial portion of the liquid carried by the grooves to be expressed outwardly and driven upwardly along the inclined forward surfaces of the baffles 24 and 26, whereby a portion of the liquid falls back into the troughs 25 and 27 and drains away to the header 45 and drain pipe 46.

Any portion of the liquid which is not trapped in the troughs 25 and 27 but instead is thrown upwardly against the inner surface of the top wall 22 will either drop from the top wall 22 into one of the troughs 25 or 27 or will continue around and become entrapped in the trough formed by the baffle 28 and the adjacent portion of the top wall 22.

Thus, it will be seen that not only do the inwardly extending internal baffles 24, 26 and 28, together with the struts 31, 33, and 34 strengthen the saveall and provide a substantially self-supporting structure, but they combine with the bottom wall and the curved top wall 22 to form a series of troughs which cooperate to entrap substantially all of the liquid expressed from the grooves of the roll 13 just before it enters the press nip formed with the rolls 12.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

1. A press assembly comprising a first press roll having a substantially circumferentially grooved surface, a second press roll forming with said first press roll a press nip having ingoing and outgoing sides, an endless porous belt passing through said nip and in contact therewith in said press nip, a saveall mounted adjacent said ingoing side of said press nip between said first press roll and said porous belt upstream of the point of contact therebetween for collecting liquid expressed at said nip, said saveall including a substantially planar bottom wall having a lower edge positioned adjacent said ingoing side of said nip and extending upstream away from said nip in closely spaced relationship to an inner surface of said porous belt, a planar baffle extending upwardly from said lower edge of said bottom wall in diverging relationship thereto, a substantially cylindrical top wall having a first longitudinal edge joined to and extending from an upper edge of said bottom wall in a direction away from said pourous belt and terminating in a second longitudinal edge overhanging said bottom wall and positioned adjacent said first press roll surface, an additional baffle having a lower longitudinal edge joined to said second longitudinal edge of said top wall, extending inwardly of said saveall and terminating in an upper longitudinal edge positioned in spaced relationship to an inner surface of said top wall and forming therewith an upper trough, and means for draining from said saveall liquid collected therein.

2. The apparatus of claim 1 further comprising a series of plate-like struts extending between and interconnected with said baffles and adjacent wall surfaces strengthening said saveall and forming a substantially self-supporting structure.

3. The apparatus of claim 1 further comprising a substantially planar baffle having a lower edge attached to an intermediate portion of said bottom wall and extending in diverging relationship thereto in a direction away from said press nip and terminating in an upper longitudinal edge positioned in spaced relationship to said inner surface of said top wall.

4. The apparatus of claim 3 further comprising a series of plate-like struts extending between and interconnected with said baffles and adjacent wall surfaces strengthening said saveall and forming a substantially self-supporting structure.

5. The apparatus of claim 1 wherein said draining means comprises an end closure member extending across and attached to one end of said top and bottom walls and said baffles, and a header attached to the opposite ends of said top and bottom walls and said baffles and draining troughs formed by said bafiles and said top and bottom walls.

6. A press assembly comprising a first press roll having a substantially circumferentially grooved surface, a second press roll forming with said first press roll a press nip having ingoing and outgoing sides, an endless porous belt, means guiding said belt in a downwardly extending run through said nip in contact therewith, a saveall mounted adjacent said ingoing side of said press nip between said first press roll and said porous belt upstream and above the point of contact therebetween, said saveall including a substantially planar bottom wall having a lower edge positioned adjacent said ingoing side of said nip sloping upwardly away from said nip in closely spaced relationship to an inner surface of said porous belt and terminating in an upper edge positioned above said nip, a planar baffle extending upwardly from said lower edge of said bottom wall in diverging relationship thereto, a substantially cylindrical top wall having a first longitudinal edge joined to and extending from said upper edge of said bottom wall in a direction upwardly and away from said porous belt, thence downwardly and toward said first press roll and terminating adjacent said first press roll in a second longitudinal edge overhanging said bottom wall and said baffle, and means for draining from said saveall liquid collected therein. 

2. The apparatus of claim 1 further comprising a series of plate-like struts extending between and interconnected with said baffles and adjacent wall surfaces strengthening said saveall and forming a substantially self-supporting structure.
 3. The apparatus of claim 1 further comprising a substantially planar baffle having a lower edge attached to an intermediate portion of said bottom wall and extending in diverging relationship thereto in a direction away from said press nip and terminating in an upper longitudinal edge positioned in spaced relationship to said inner surface of said top wall.
 4. The apparatus of claim 3 further comprising a series of plate-like struts extending between and interconnected with said baffles and adjacent wall surfaces strengthening said saveall and forming a substantially self-supporting structure.
 5. The apparatus of claim 1 wherein said draining means comprises an end closure member extending across and attached to one end of said top and bottom walls and said baffles, and a header attached to the opposite ends of said top and bottom walls and said baffles and draining troughs formed by said baffles and said top and bottom walls.
 6. A press assembly comprising a first press roll having a substantially circumferentially grooved surface, a second press roll forming with said first press roll a press nip having ingoing and outgoing sides, an endless porous belt, means guiding said belt in a downwardly extending run through said nip in contact therewith, a saveall mounted adjacent said ingoing side of said press nip between said first press roll and said porous belt upstream and above the point of contact therebetween, said saveall including a substantially planar bottom wall having a lower edge positioned adjacent said ingoing side of said nip sloping upwardly away from said nip in closely spaced relationship to an inner surface of said porous belt and terminating in an upper edge positioned above said nip, a planar baffle extending upwardly from said lower edge of said bottom wall in diverging relationship thereto, a substantially cylindrical top wall having a first longitudinal edge joined to and extending from said upper edge of said bottom wall in a direction upwardly and away from said porous belt, thence downwardly and toward said first press roll and terminating adjacent said first press roll in a second longitudinal edge overhanging said bottom wall and said baffle, and means for draining from said saveall liquid collected therein. 